Croatian football club GNK Dinamo Zagreb has confirmed midfielder Arijan Ademi failed a doping test after the Champions League win of the Croatian side over Arsenal in September.

The 24-year-old Zagreb played the full 90 minutes of 2-1 home victory of Dinamo at the start of the Group F campaign. Result of the match is not believed to be affected by outcome of test on the B-sample of Ademi. If his B-sample also test positive, Ademi faces a doping ban of two years

Ademi has played for both Croatia and Macedonia. He also featured in the 5-0 thumping of Bayern Munich by Dinamo in last week's second round of group fixtures.

Arsenal is facing the prospect of crashing out in the group stage unless they can take points from Bayern Munich after losing their opening games in the competition.

A statement on the Dinamo Zagreb website read UEFA, the governing body of football in Europe, started disciplinary proceedings against its player Arijan Ademi due to a positive doping test after the Champions league match Dinamo - Arsenal, UEFA instigates disciplinary proceedings against Ademi. The statement also said the team's players are constantly under doping control, especially during the UEFA competitions, and this is the first time we are facing a situation like this one. It was further added that the team was surprised because Ademi was selected for doping control six times this year and results were negative every time, as well as results of every other player who was selected for doping control by UEFA or Croatian Anti-Doping Agency.

The statement on the Dinamo Zagreb website added GNK Dinamo nor the player are not allowed to make any statement during a disciplinary procedure and the team will inform all shortly about the progress of this situation.

The Croatian-born Macedonian professional footballer was born on 29 May 1991 and started his professional career at Šibenik. Ademi, who currently plays for GNK Dinamo Zagreb and Macedonian national team, made his debut for the senior squad on 22 March 2008 aged just 16 years and was transferred to reigning Croatian champions Dinamo Zagreb on 16 June 2010.

Ademi participated at the 2010 UEFA European Under-19 Football Championship and debuted for the Macedonia national team in an official match on 9 October 2014. Ademi scored his first league goal on 25 July 2009 in a match against Croatia Sesvete which Šibenik won 2–1. The football player was also the youngest player that captained any Prva HNL club in the 2009 season. Ademi scored his first international goal on 17 September in a friendly match against Bosnia and Herzegovina under-19 team in Županja, which finished with a 2-2 draw. Croatian coach Niko Kovač decided not to pick Ademi for the 2014 FIFA World Cup squad in Brazil and he decided to play for Macedonia. Ademi made his official debut in a UEFA Euro 2016 qualifying match against Luxembourg on 9 October 2014. Arijan Ademi is a cousin of the Macedonian professional football player Agim Ibraimi.